Confusing 12 volt conversion.

[Atrange07]

I bought a used cucv from a guy in Arizona. he supposedliy did a 12 volt conversion 1 alternator is removed
he added a turbo, electric fuel pump and and a/c unit. im trying to figure out a way to reinstall the second
alternator to help charge at at 14 volts and not 28. Currently just the drivers side alternator is hooked up
and I had to be jumped started at the gas station. once I got home I tested the alternator and it is only putting out 12 volts. both batteries are dead. so Im going to replace them but, I was wondering if there was a way to wire up both alternators to charge the batteries at 14volts

 

[ke5eua]

Load test your batteries. The alternator will not output 28 volts, that is why it has two stock in its 24v state.

How are the batteries wired, series, parallel?

Normal charging should be around 13.8 volts, but if your batteries are dead then once the alternator reached it max amperage output the voltage will start to drop and that it why you are seeing 12v as that is the minimal voltage it will output.

Charge the batteries on a slow charge and load test them. Also check the gravity levels to see if any cells are dead.

IMO it sounds like a battery issue.

 

[rustyshakelford]

Sounds like the alternator is bad. As mentioned, load test the batteries and replace the alt. I got a 100 amp from autozone for less than $100

brett

 

[Atrange07]

he had 2 commercial batteries with only 660 cca, I swaped them out I have to new batteries with 950 cca. then I checked the alternator output, its putting out 12.5. It looks to be a rebuild of the original. the guy I bought from threw in the alternator he took off when he converted it. it looks the same as the new one, just old and covered in Arizona dust. I swapped it in, and it is only putting out 12.5 volts as well. I was looking through the threads and I saw that
someone was offering a 150 replacement. would you guys recommend that.

 

[ke5eua]

he had 2 commercial batteries with only 660 cca, I swaped them out I have to new batteries with 950 cca. then I checked the alternator output, its putting out 12.5. It looks to be a rebuild of the original. the guy I bought from threw in the alternator he took off when he converted it. it looks the same as the new one, just old and covered in Arizona dust. I swapped it in, and it is only putting out 12.5 volts as well. I was looking through the threads and I saw that
someone was offering a 150 replacement. would you guys recommend that.

There is more to this than just swapping alternators. If you put in another and it is outputting 12.5 volts and the batteries are indeed good I would check the regulator.

Charging system is very simple. Field is energized by the available voltage in the batteries giving you your output.

 

[porkysplace]

There is more to this than just swapping alternators. If you put in another and it is outputting 12.5 volts and the batteries are indeed good I would check the regulator.

Charging system is very simple. Field is energized by the available voltage in the batteries giving you your output.

The alternators are internally regulated , the odds of 2 alternators having a bad regulators and putting out the exact same voltage is slim. There is another issue .

Is it the Roscommon Conversion ?

 

[MarcusOReallyus]

The alternators are internally regulated , the odds of 2 alternators having a bad regulators and putting out the exact same voltage is slim. There is another issue .

Yep.

Atrange, you need to find and fix what's wrong before you look into adding an alternator. You might bandaid the problem that way, but more likely, you'll just be throwing money & time at it for nothing.


Some detailed photos would help folks here figure out your conversion to maybe steer you in the right direction.

 

[ke5eua]

What is the voltage on the field wire when the truck is running?

 

[Atrange07]

I tried the link to the Roscommon conversion and it didn't work for me, it wouldn't pull up

 

[M1008driver]

http://www.roscommonequipmentcenter.com/page26.html

Then use Adobe Reader and open M1008 & M1009 - Electric Systems to 12 Volt Conversion

 

[Crash_AF]

Does your Alt1 light come on when you first turn the key on? If it doesn't, that's your problem. I'll bet you have a wiring problem between the alternator and the dash. Check the condition of that plug on the top of the alternator. Also make sure you don't have any blown fuses.

Joe

 

[Atrange07]

sorry been busy with work haven't been able to get on here or take pictures. Neither of the gen lights come on when I turn the key

 

[Crash_AF]

You need to figure out why #1 doesn't come on before you go any further. The Gen 1 light MUST come on in order for the alt to produce power. Just the nature of the design.

Joe

 

[rsh4364]

My 1009 is still 24/12 volt,but I was looking over rosscommon conversion and when I got to step 8 it says to remove a condenser from pass. side alt.Mine does not have this condenser.Any reasons why? Everything seems to work fine as is but a little concerned when something is missing! My volt meter is right on green line red line when running.Reads 14.5-14.6 volts on multimeter on batts. when at idle.Is this normal?

 

[Warthog]

External condensers are usual removed during rebuilds and replacements. It is not needed.

 

[Atrange07]

You need to figure out why #1 doesn't come on before you go any further. The Gen 1 light MUST come on in order for the alt to produce power. Just the nature of the design.

Joe

its been quite awhile since , i was on here, figured i would write the fix. So both Alternators did need to be rebuilt. Once reinstalled on in the truck it still was not charging correctly and no Gen 1 light. After examining the issue, i added a ground from Drivers side alterntor to engine block. No charging correclty and i have Gen 1 light coming on like it is suppose to.

 

[cucvrus]

its been quite awhile since , i was on here, figured i would write the fix. So both Alternators did need to be rebuilt. Once reinstalled on in the truck it still was not charging correctly and no Gen 1 light. After examining the issue, i added a ground from Drivers side alterntor to engine block. No charging correclty and i have Gen 1 light coming on like it is suppose to.

I am happy that after 8 years you have the alternators charging. Happy Thanksgiving.